feat: Add Notice documentation header check.

[bdferris-v2]

As part of automated Notice documentation extraction (#1324), this PR adds a unit-test to enforce that each Notice has a Javadoc documentation header.

• Run the unit tests with gradle test to make sure you didn't break anything
• Format the title like "feat: [new feature short description]". Title must follow the Conventional Commit Specification(https://www.conventionalcommits.org/en/v1.0.0/).
• Linked all relevant issues
• Include screenshot(s) showing how this pull request works and fixes the issue(s)

[github-actions]

✅ Rule acceptance tests passed.
New Errors: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Errors: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
New Warnings: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Warnings: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
0 out of 1426 sources (~0 %) are corrupted.
Commit: 805e74f
Download the full acceptance test report here (report will disappear after 90 days).
✅ Rule acceptance tests passed.

[github-actions]

✅ Rule acceptance tests passed.
New Errors: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Errors: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
New Warnings: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
Dropped Warnings: 0 out of 1426 datasets (~0%) are invalid due to code change, which is less than the provided threshold of 1%.
0 out of 1426 sources (~0 %) are corrupted.
Commit: dcc5e2b
Download the full acceptance test report here (report will disappear after 90 days).
✅ Rule acceptance tests passed.